The present disclosure relates to a sliding cam system for an internal combustion engine.
Valve-controlled internal combustion engines comprise one or more controllable admission and exhaust valves for each cylinder. Variable valve trains enable a flexible actuating of the valves for changing the opening time, closing time, and/or valve lift. In this way, the engine operation can be adapted to a specific load situation, for example. For example, a variable valve train can be realized by a so-called sliding cam system.
From DE 196 11 641 C1 there is known an example of such a sliding cam system, making possible the activation of a gas exchange valve with several different lift curves. For this purpose, a sliding cam is mounted on the cam shaft in a rotationally fixed but axially movable manner, having at least one cam section with several cam tracks, having a lift contour in which an actuator is inserted in the form of a pin, radially from the outside, in order to generate an axial displacement of the sliding cam. Thanks to the axial displacement of the sliding cam, a different valve lift is established for the particular gas exchange valve. The sliding cam, after its axial displacement relative to the cam shaft, is locked in its relative axial position on the cam shaft in that at least one spring-loaded detent ball, which is received and mounted in the cam shaft, engages in at least one detent groove in dependence on the relative axial position.
The sliding cam system may take up significant design space. In particular, an arrangement of the actuators for the moving of a cam carrier (sliding cam) may represent a challenge when space is tight. Typically, the actuators are fastened to a frame connected to the cylinder head or cylinder head cover.
From DE 10 2011 050 484 A1 there is known an internal combustion engine with multiple cylinders, a cylinder head, and a cylinder head cover. For the activating of gas exchange valves, there is provided at least one rotary mounted cam shaft with at least one sliding cam able to move axially on the respective cam shaft. The respective sliding cam has at least one gate section with at least one groove. An actuator is provided to bring about an axial displacement of the respective sliding cam. The actuator is mounted in the cylinder head or in the cylinder head cover.